Degradação do herbicida 2,4-D (ácido diclorofenoxiacético) via radiação UV

Abstract

Problems with the environment have been increasing and gaining a lot of visibility throughout the world, fostering the development of researches with the purpose of finding treatment methods to mitigate such questions. The contamination of water resources by agrochemicals is a growing preoccupation in our country. For this reason, the present project evaluated the efficiency of the 2,4-D (dichlorophenoxyacetic acid) herbicide degradation via heterogeneous photocatalysis, adsorption and photolysis, using P25 and Niobium Pentoxide (Nb2O5), calcinated at 400, 500 and 600 °C, as catalysts. For the photocatalysts characterization the following techniques were used: X-Ray Diffraction (XRD) and Photoacoustic Spectroscopy. The photocatalytic experiments in a batch reactor were arranged with the variation of the parameters: pH and catalyst concentration. For the optimal condition found, were also conducted adsorption tests and in continuous flow reactor. The UV-VIS scanning observed that the Nb2O5 was not effective, as well as the P25 immobilized in alginate, adsorption and photolysis. The same cannot be affirmed for the P25 in suspension, with which a reduction of approximately 35% from the contaminant’s concentration was achieved, for the batch reactor, and 21% for the continuous flow reactor, when using a mass of 40 mg.L-1 and pH 4.